The use of vehicle suspensions of the type commonly known as a Mac Pherson strut is increasing, especially for steerable front suspensions. In this type of suspension, a piston type damper commonly has a cylindrical reservoir and a piston rod contained therein. The bottom of the cylindrical reservoir is attached to the steering knuckle, the top of the piston rod is rigidly attached to an elastomer mount on the vehicle, and a shock absorbing compression coil spring surrounds the damper and is seated between an upper and a lower spring seat. In a steerable suspension, the top coil of the spring turns relative to the upper mount or the cylindrical reservoir turns relative to the lower coil of the spring. In either case, it is desirable to interpose a bearing between the two relatively rotating parts to facilitate steering and handling. U.S. patent to Pflughaupt et al, No. 4,260,117, shows an anti-friction bearing unit interposed between a lower spring seat and a bearing seat on the cylindrical reservoir of the damper.
There may be a problem in suspension structures which place the bearing between the lower spring seat and the damper. The lower part of the suspension may present a more harsh environment, increasing the need for sealing and shielding of the bearing.